Microbicides are products to be used by women for placing into the vagina to prevent passing HIV from 1 person to another during sex. Studies have shown 2 investigational microbicides, BufferGel and PRO 2000/5 Gel, to be safe and acceptable for women and HIV-negative men. It is important to see if the side effects of these products are the same in men as those in women and to see if there is any difference in the side effects between circumcised and uncircumcised men.